This project is concerned with characterizing more completely the physiologic aspects of the hereditary syndrome of hypothyroidism which occurs in the Obese strain of chicks. The main objective is to identify the non hereditary factors and their sequence of manifestation in the development of the syndrome so that ultimately this strain might serve as an animal model of a type (wholly or partially) of thyroiditis in human beings. BIBLIOGRAPHIC REFERENCE: Newcomer, W. S. Thyroxine and triiodothyronine in blood after ingestion of iodinated casein by chicks. Poultry Science (January, 1976).